Karen uses her credit card to purchase a new television for 695.20. she can pay off up to $325.00 per month. the card has an annual rate of 17.9% compounded monthly. how much will she pay in interest?

you can use the following online calculator to answer your question. 
 http://www.arachnoid.com/lutusp/finance.html 
 you would make the folowing entries: 
 Present Value = 695.20
 Future Value = 0
 Number of Payments is left blank because you want to solve for that.
 Payment Amount = -325.00
 Interest Rate per period = 17.9% per year divided by 12 =  1.491666667% per month.
 Payment At is at End. 
 click on the NP button and it will tell you the number of months required for the loan to be fully paid off. 
 the calculator will show you that it will take 2.19 months for you to fully pay off the loan of $695.20 when you are paying it off at $325.00 at the end of each momth and the interest rate if  1.491666667% per month. 
 now that you know how long it takes for you to pay it off, you can determine what the interest amount is that you paid. 
 multiply your payment of 325 per month by 2.19 months to get a total payment of $ 711.75
 your loan was for $695.20. 
 the difference is the amount of interest you paid. 
 that will be $711.75 - $695.20 =16.55 $\ 
 you paid $16.55 in interest.